54<> 



THE ANIMAL PARASITES OF MAN 



in cracks in the boards, sweepings, spittoons, etc. ; they produce legless 

 larvze consisting of fourteen segments, which, after about eleven days, 

 are transformed into pupae; after another eleven days the flea emerges. 



FlG. 382. Pulex irritans. 14/1 



FIG. 383. Larva of flea. 

 Enlarged/ (After Railliet.) 



FIG. 384. Pulex serraticeps. 22/1. 



Boni; Fleas live in human dwellings all over the world, and periodically pass on to 

 persons to suck their blood. They may deposit their eggs on very uncleanly 

 individuals, and even undergo development, therefore it is possible to find larvae 

 and pupae on such persons. 



The dog flea, Pulex serraticeps, is easily distinguished from the flea of man by 

 the large thick bristles on the posterior margin of the first thoracic ring (fig- 384). 



Genus. Xenopsylla, Glink. 

 Xenopsylla cheopis, Rothschild. 



This is the common rat flea of tropical countries. Rothschild * 

 says : "Although practically cosmopolitan, it cannot apparently flourish 

 in temperate and cold climates." 



1 Bull. Ent. Res. y 1911, i, pt. 2, p. 92. 



